Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

Wildfire can drastically increase the probability of debris flows, a potentially hazardous and destructive form of mass wasting, in landscapes that have otherwise been stable throughout recent history. Although there is no way to know the exact location, extent, and severity of wildfire, or the subsequent rainfall intensity and duration before it happens, probabilities of fire and debris-flow occurrence for different locations can be estimated with geospatial analysis and modeling efforts. The purpose of this report is to provide information on which watersheds might constitute the most serious, potential, debris-flow hazards in the event of a large-scale wildfire and subsequent rainfall in the Sandia and Manzano Mountains.

On World Water Day, the World Resources Institute (WRI) has released a study that maps for the first time the water resources available to support fracking in the world’s largest shale exploration areas. The study, “Global Shale Gas Development: Water Availability and Business Risk,” found that 40 percent of countries with the largest shale energy resources could suffer from water stress: competing demands on their renewable water supply that could make it problematic to use that water for fracking.

A report released today by the chief science advisor to the United Kingdom energy agency on the carbon effects of burning wood biomass for energy will significantly change UK energy policy with significant implications for the rapidly expanding wood pellet industry in the southern United States. Already in response to the report, the U.K. Department of Environment and Climate Change (DECC) announced that beginning next year, government subsidies will not be provided to wood biomass sources that do not meet a carbon reduction target.

However, the scientists cautioned that major disturbances, such as droughts, wildfires and hurricanes, can all affect the amount of carbon sequestered in a given year. Large droughts that happened twice in the U.S. in the past decade reduced the carbon sink about 20 percent, compared to a normal year.

“With climate change, we may get more extreme or frequent weather events in the future than we had before,” Law said. “About half of the United States was affected by the major droughts in 2002 and 2006, which were unusually severe in their spatial extent and severity. And we’re now learning that this can have significant effects on the amount of carbon sequestered in a given year.”